Time Machine can be used with most external USB hard drives as well as many Network devices. For external drives, the device must be formatted as HFS+ in order to be used with Time Machine. Time Machine backups to external USB drive can be encrypted, adding a layer of data protection and privacy. For more information, please refer to Answer ID 27398: How to Encrypt a Time Machine Backup

How to Backup

To perform a Time Machine backup on macOS, connect the drive to your Mac and make sure it is formatted for Time Machine backups

Critical:
The instructions in the article below are designed to help repartition and format a hard drive. This process is Data Destructive and cannot be undone. Once the process begins, ALL THE DATA ON THE DRIVE WILL BE LOST!